yo
firstly I'm not an expert in any sense and I'm sure somebody who knows a heap more than I do will sort you out in a minute but heres a pointer or two to get you goin:
thats not a very good set up for audio: expect to spend a bit of cash for something thats not gonna sound completely shite.
I'd recommend getting either a decent sound card or an audio interface and possibly even a mixer, if you're gonna be recording other types of audio (vocals etc) its probably worthwhile splashing out on a mic too, but make sure your outboard gear supports phantom power as most decent mics operate on that.
the above is really basic and only my two cents. for a great website on all things home studio related have a look at:
Tweak's Guide to the Home and Project Studio
which i found to be massively helpful. hope thats a start at least!